ABSTRACT
BACKGROUND: Bcl-2 family proteins play a central role in regulating apoptosis. In human, over 20 members of this family have been identified to date. Bfl-1, a member of the Bcl-2 family, has been known to retard apoptosis in various cell lines. However, the function of Bfl-1 remains unclear. METHODS: In order to investigate the Bfl-1 function, we employed yeast two-hybrid system to identify the proteins which are capable of interacting with Bfl-1. The interaction of inhibitor kappaB kinase-beta (IKK-beta) and Bfl-1 was confirmed using glutathione S-transferase pull down assays. To determine which regions of IKK-beta were required for interaction with Bfl-1, we constructed 12 deletion mutants of IKK-beta and 5 deletion mutants of Bfl-1. RESULTS: Bfl-1 interacted with the C-terminal region of IKK-beta which is a subunit of IKK complex, and IKK-beta activity is very important in the NF-kappaB related pathway. In addition, the amino acids 673-745 of IKK-beta were important for Bfl-1 interactions, and amino acids 1-484 of Bfl-1, including Bcl-2 homology domains (BH1, BH2, BH3, BH4), were crucial for IKK-beta interactions. CONCLUSIONS: IKK beta C-terminus contains many serine residues as binding partner of Bfl-1. Our results suggested that Bfl-1 is involved in the NF-kappaB activation through interaction of IKK-beta and Bfl-1. Further studies need to be performed to understand functions of the IKK-beta and Bfl-1 associated with the regulation of the NF-kappaB activation pathway.
Subject(s)
Humans , Amino Acids , Apoptosis , Cell Line , Glutathione Transferase , I-kappa B Kinase , NF-kappa B , Serine , Two-Hybrid System TechniquesABSTRACT
Staphylococcus aureus infections are often life-threatening. Relatively little is known about the host response to these infections, in particular, the implication of apoptosis induced by this microorganism. In this study, we have shown that S. aureus was cytotoxic to J774A.1 cell, a murine macrophage cell line. The cell death mediated by S. aureus occurred through apoptosis, as shown by increase in the proportion of fragmented host cell DNA. Although phagocytosis and NO production had important role in the induction of apoptosis, the contact between bacteria and host cells was not essential for this pathway. A certain bacterial product could also induce typical caspase-dependent apoptosis of J774A.1 cell. It is expected that new interpretation may be possible to host-parasite relationship based on these results.
Subject(s)
Animals , Mice , Apoptosis , Bacteria , Cell Death , Cell Line , DNA , Host-Parasite Interactions , Macrophages , Phagocytosis , Staphylococcus aureus , StaphylococcusABSTRACT
Mycobacterium tuberculosis is capable of growing and survival within macrophage. The purpose of this study was to identify the genes regulated by infection of mycobacteria in human monocytic THP-1 cells. We used the differential display reverse transcriptase polymerase chain reaction (DD RT-PCR) and nothern blot analysis to confirm the differentially expressed genes from THP-1 cells infected with live Mycobacterium tuberculosis H37Rv, heat-kille Mycobacterium tuberculosis H37Rv and live Mycobacterium bovis BCG. Among many up or down-regulated clones, 27 clones were sequenced and compared with known genes on GenBank. Thirteen of over-expressed clones from THP-1 cells infected with live Mycobacterium tuberculosis H37Rv were identical to human prothymosin alpha, eight were novel clones and six clones showed homology with Human ferritin H chain, Escherichia coli bgl, Mouse RNA-dependent EIF-2 alpha kinase, E. coli htrL, Hyaluronan receptor and T cell receptor. Our result suggests that Mycobacterium tuberculosis might regulate prothymosin alpha gene transcription in monocytic THP-1 cell.
Subject(s)
Animals , Humans , Mice , Hyaluronan Receptors , Clone Cells , Databases, Nucleic Acid , Escherichia coli , Eukaryotic Initiation Factor-2 , Ferritins , Macrophages , Mycobacterium bovis , Mycobacterium tuberculosis , Mycobacterium , Phosphotransferases , Receptors, Antigen, T-Cell , Reverse Transcriptase Polymerase Chain Reaction , Up-RegulationABSTRACT
We experienced a case of acute renal failure by oxalate poisoning in a 44-year-old Korean woman. She presented with hematemesis and epigastric pain after drinking of oxalate in a suicidal attempt. After admission, acute renal failure was developed and the patient was treated with hemodialysis. On renal biopsy, there were numerous calcium oxalate crystals which appeared clearly in Hematoxylin-eosin stained sections and were refractile under polarized light microscope. We report a case of acute renal failure by oxalate poisoning with review of the literature.